Light ion heating in ECR ion sources

The experiments described here were performed at a 5 GHz electron-cyclotron-resonance ion source (ECRIS) with a magnetic hexapole. The discharge was run in argon. By launching a fast magnetoacoustic wave from the high-field side (end-on) we heated hydrogen ions - present in traces from the residual gas - at their fundamental ion cyclotron resonance (ICR) frequency of 2.2 MHz with 5 W only. As a consequence the currents of Ar"q"+-ions extracted from the source were significantly increased for q#>=#5 while the currents of lower charged argon ions were decreased, indicating an enhanced plasma confinement. However, a reduction of the hydrogen content in the residual gas resulted in a reversal of the effect of ICR heating. (orig.)Available from TIB Hannover: RO 9159(46)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman